Dutch tennis player Robin Haase has received some 30 death threats from gamblers who claim to have lost money on his matches, the Volkskrant reports on Wednesday.

The threats have been made via email, social media channels and Haase’s own website. The players’ union ATP has now started an investigation into the threats against Haase and other players, the Volkskrant said.

One threat, received after Haase lost a final in an Italian competition read:  ‘M*****F*****. I’ve lost a lot of money on you because you sold your match. I’ll finish you off.’

Haase told the paper the same person had already threatened him after the first round, when he won. Haase is currently ranked 59th in the world.